This invention relates generally to process and apparatus for the recovery of elemental chlorine from hydrogen chloride, and more particularly, concerns a two stage, continuous reaction process employing a carrier catalyst system.
Hydrogen chloride is available from many chemical processes as a by-product. It may be obtained as an anhydrous gaseous stream or as an aqueous solution. The recovery of hydrogen chloride from chlorination processes is necessary because of environmental and ecological reasons. The economic disposal of this hydrogen chloride has been a very difficult task which has received much study for many years.
The process described herein makes use of technology best defined as a carrier catalyst system. In previous attempts to recover chlorine from hydrogen chloride, a catalyst system consisting of a metal or a group of metals, supported on alumina or silica, has been used with a fair amount of success, but with certain serious problems. These problems included the extreme difficulty of separating the gases which evolve from the catalytic reactor because of the simultaneous presence of hydrogen chloride, chlorine, water, oxygen, nitrogen, and other materials, all in a single gas stream. Further, it was found that the catalyst used had a relatively short life due to the high volatility of the metals used in the chlorine atmosphere at an economic rate.